Often it is desirable to apply a clamp to hold an object in position. For example, for an exposure apparatus, it is often desirable to hold a stage and its load in position. For example, when a current stage position needs to be held for a while, the stage can be clamped to save power and inhibit the stage movers from heating up. Also, for systems that combine a low-stiffness long-range coarse stage in series with a high-stiffness short-range fine stage, the coarse stage can be clamped in between long range travels to increase the stiffness of the overall system while the stiffer fine stage accommodates short-range motion.
Unfortunately, the forces and stresses from the clamping action of a clamp can cause deformations and motions that are too large for maintaining position within nano-scale tolerances.